1. Technical Field
The present invention relates to a seat belt retractor for a vehicle. More particularly, the present invention relates to a seat belt retractor having both a relatively strong power spring and a relatively weak comfort spring for biasing the seat belt in a belt retraction direction. The retractor of the invention also has a mechanism which is settable to prevent the relatively strong spring from acting on the seat belt so that only the relatively weak spring then biases the seat belt in the belt retraction direction.
2. Prior Art
Seat belt retractors having a relatively strong power spring and a relatively weak comfort spring for biasing a seat belt in a belt retraction direction are known. U.S. Pat. Nos. 4,126,282, 4,310,128, and 4,383,658 illustrate examples of such retractors. Each of these patents discloses a seat belt retractor having a strong power spring and a relatively weak comfort spring acting to retract belt webbing. The strong power spring acts between the retractor frame and a ratchet wheel. The comfort spring acts between the ratchet wheel and the spool of the retractor on which the seat belt is wound. When the seat belt is paid out and fastened around a vehicle occupant, a pawl locks the ratchet wheel so that it cannot rotate in the belt retraction direction. The relatively weak comfort spring then acts to bias the belt in the belt retraction direction. If the occupant moves in his seat, he moves against only the bias of the relatively weak comfort spring.